(1) Field of the Invention
This invention relates to an electrophotographic device having a processing head which comprises four separate stages charging/exposing, developing, drying, and fixing, and which simultaneously processes a plural number of frames of a recording film.
(2) Description of the Prior Art
Picture image data is generally recorded on a microfilm or the like by a 5-stage processing which comprises charging, exposing, developing, drying and fixing in a wet-type electrophotographic recording system. In short, a film or an electro-photosensitive material is charged on the surface thereof by corona-discharge in a charging process and forwarded to an exposing process. In the exposing process, picture image data to be recorded is projected and recorded on the film via an optical system as an electrostatic latent image. The film with the electrostatic latent image is fed to a developing process, where a developer is applied on the photosensitive surface thereof, and toner is made to electrically adhere according to the pattern of the latent image. Then, the film is passed to the drying process to dry unnecessary or excess developer. The toner which electrically adheres is fused in a fixing process, thereby recording the picture image data on the film, almost permanently. If a special liquid developer is used, it may be dried and fixed simultaneously. In such a case, the drying process includes the fixing process and the film may be finished completely by a four-stage process.
As it is possible to forward the image recording process by a frame of a film in such an electrophotographic system, it can advantageously reproduce picture image data immediately. Also, since the electro-photosensitive member is not photosensitive until it is charged, the film can be inserted under daylight conditions and it is more advantageous compared with conventional recording systems using a silver halide photographic material. Therefore, it has been applied in various fields.
In the above electrophotographic recording system, as the toner electrically adheres to an electro-photosensitive member as described above, it is necessary to immediately fix it. The above processing is, therefore, conducted on each frame consecutively and continuously. There have been proposed various types of recording heads which can conclude image processing in a short time and have processing sections arranged in a space-saving manner.
A conventional head is shown in FIGS. 1(a) and 1(b). The recording head 10 in FIG. 1(a) is provided with a charging/exposing section 11, a fixing section 12 adjacent thereto, a liquid-removing section 13, and a developing section 14, arranged in that order, and all the sections other than the liquid-removing section 13 have openings of a size corresponding to a frame of a film. A frame of the film is uniformly charged and projected with an image at the charging/exposing section 11, then passed to the developing section 14 via the fixing section 12 and the liquid-removing section 13 and processed for development. It then is reversed to be passed in the direction toward the liquid-removing section 13 to remove the liquid and dry while moving toward the fixing section 12. The fixing process is conducted in the section and at the same time a new frame adjacent to the first frame is charged and exposed at the charging/exposing section.
The recording head 20 shown in FIG. 1(b) is an example where a main body 21 is slidably provided in the advancing direction of the film and comprises of a developing section 22, an exposing section 23, a charging section 24, and a drying section 25 arranged in due order. In the recording head 20, the main body 21 is moved in the advancing direction of the film toward a frame thereof which is held stationary at a predetermined position to conduct processes from charging to developing consecutively, by the charging section 24, the exposing section 23, and the developing section 22. Then, the main body 21 is reversed in movement so that the drying section 25 comes to face the frame to conduct drying and fixing operations. As reference materials concerning FIG. 1(a), there are U.S. Pat. No. 3,972,610 and U.S. Pat. No. 4,082,442, and other. As for FIG. 1(b), there is Japanese Patent Publication No. 54-13786.
The conventional processing heads for recording however, have a common defect: a complex feeding mechanism because the relative moving direction of the head must be reversed after developing. Also, it is detrimental in processing as far as efficiency is concerned because plural processes cannot be conducted simultaneously, and the intervals between processes tend to become extended. Further, the processing head for recording shown in FIG. 1(a) is detrimental in that since a pressure reducing pump is used for sending the developer into the developing chamber, the structure of the liquid passage system becomes complicated and thus expensive.